Thioethers and methods for obtaining the same



Patented Oct. 4, 1949 I UNITED STATES PATENT OFFICE THIOETHERS AND METHODS FOR OBTAINING THE SAME George Rieveschl, Jr., Grosse Pointe Woods, Mich., assignor to Parke, Davis & Company, Detroit, Mich., a corporation of Michigan No Drawing. Application August 5, 1946, Serial No. 688,427

8 Claims. (01. 260-570) 1 2 This invention relates to certain basically substituted thioethers and to methods .for obtain- D ing thesame. This application is a continuationin-part of my copending application, Serial No. R1 (HI-X 531,639, filed April 18, 1944, now Patent No. 5. 2,421,714 issued June 3, 1947.

More particularly, this invention relates to- Wlth an alkali metal salt of w-aminoalkyl mercapc-N-substituted aminoalkyl benzhydryl thiotan of the formula ethers, the free bases of which have the formula R: 12, w-son, ..n R, cn-s CHi).N under the same conditions used to bring about U R the reaction between an alkali metal salt of a benzhydryl mercaptan and an aminoalkyl halide.

where n is one of the integers two and three, R: In the f 9 mulae B2, B R4 and n have and R: are the same or difierent substituents and the slgmficahce as Prevlously giVeI1, M is represent hydrogen, an alkyl radical containing 'f ,alkah metal and X is a chlorine, bmmme 1 or 2 carbon atoms or an alkoxy radical containing 1 or 2 carbon atoms, R3 and R4 are the The compquilds the Present invfmtion same or diflerent alkyl radicals containing 1 to 3 usefu! as antlhlstahhne agents and as mtermedl carbon atoms inclusive or R3 and R4 taken with ates m g synthesls 0f other Valuable Organic --N may be a saturated six-membered heterocompouh cyclic ring such as piperidine, a methyl substi- The mventlon 15 illustrated by the following tuted piperidine, morpholine, a methyl substiexamples- 1 tuted morpholine, thiomorpholine and the like. Ex 18 The compounds of this invention may be obtained amp m g ggi benzhydml as the free base having the formula given above 7 or they may be obtained in the form of their acid CH addition salts with organic and inorganic acids. CH 8 Some typical examples of these salts are the hy- I Omani drobromide, hydrochloride, phosphate, sulfate, O citrate, oxalate, tartrate, smicylatebenzoate and acetate salts. 32.3 g. of S-benzhydryl lsothiourea hydrobro-- I have found that compounds of the above genmide is dissolved in 50 cc. of ethanol and 15 g. of eral formula may be obtained in high yields by sodium hydroxide in 20 cc. of Water added to the the reaction of an alkali metal salt of a benzsolution with stirring. The solution of the sohydryl mercaptan of the formula dium salt of benzhydryl mercaptan thus obtained R 40 is warmed for a few minutes and then treated with a solution of 23.3 g. of p-dimethylamino- Q ethyl bromide hydrobromide in 50 cc. of alcohol.

11-s- The mixture is heated under reflux for one hour;

I cooled and diluted with water. The solution is extracted with ether, the ether extracts washed with an mammoalkyl halide of the formula with water and dried. 0n adding an excess of alcoholic hydrogen chloride to the ether solution R, of the base the hydrochloride salt of fi-dimothylaminoethyl benzhydryl thioether is obtained as a white solid which may be purified byrecrystallization from isopropanol-ethyl acetate mixture; in an organic solvent or a water-organic solvent 3 181-30 mixture. Some of the solvents which have proved satisfactory are methanol, water-methanol mix Example 2 Y'D2methymmmopropw benzhydryz ture, dilute ethanol, absolute ethanol, isopropathwether n01, aqueous dioxane, benzene, toluene, terpentine, pyridine, di-n-butyl ether and xylene. Q These new thioethers may also be prepared by ori-s-omonlonm the reaction of a benzhydryl halide of the formula 20 g. 01' benzhydryl mercaptan is dissolved in 200 cc. of 50% methanol containing 8 g. of sodium hydroxide and the resulting solution treated with 16.5 g. of 'y-dimethylaminopropyl chloride hydrochloride. The mixture is heated under reflux for three hours, diluted with water and extracted with ether. The ether solution is extracted with sodium hydroxide, washed with water and then extracted with dilute hydrochloric acid. The acidic extracts are made alkaline in the cold with 10% sodium hydroxide solution, the free base extracted with ether and the ether extracts dried. The dry ether solution is treated with an excess of dry hydrogen chloride and the white hydrochloride of 'y-dimethylaminopropyl benzhydryl thioether which separates, collected and purified by recrystallization from isopropanol-ether mixture.

Example 3.p-Diethylaminoethyl thioether benzhydryl A solution containing 22.2 g. of the sodium salt of benzhydryl mercaptan and about 7 g. of free sodium hydroxide is prepared by adding a solution of g. of sodium hydroxide in 30 cc. of water to a rapidly stirred solution of 32.3 g. of S-benzhydryl isothiourea hydrobromide in 100 cc. of ethanol. The solution is warmed for a -few minutes and then 16 g. of p-diethylaminoethyl chloride hydrochloride in 50 cc. of alcohol added to the warm solution of the mercaptan salt. The mixture is refluxed for one hour, cooled and diluted with water. The solution is extracted with ether, the ether extracts washed with water and dried. The free base of the fi-diethylaminoethyl benzhydryl thioether present in the ether solution is converted to the hydrochloride by treatment with an excess of alcoholic hydrogen chloride. The hydrochloride salt is collected, washed with ether and purified by recrystallization from isopropanol-ether mixture.

CH-S-CHzCHzCHzN 20 g. of benzhydryl mercaptan is added to 200 cc. of 70% ethanol containing 11.5 g. of potassium hydroxide. After all .the mercaptan has dissolved 28.7 g. of v-l-piperidylpropyl bromide hydrobromide is added in small portions with stirring and the resulting mixture refluxed for three hours. Most of the alcohol is removed by distillation, the residue diluted with water and extracted with ether. The ether extract is washed with water, dried and treated with an excess of dry gaseous hydrogen bromide. The hydrobromide salt of Y1-piperidylpropyl benzhydryl thioether which separates as a white fiufi'y solid is collected and purified by recrystallization from isopropanol-ether mixture.

By substituting an equivalent amount of 7-(3- methyl-l-piperidyl)-propy1 bromide hydrobromide for the piperidyl alkyl halide in the above procedure one obtains 'y-(3-methyl-1-piperidyl) p py benzhydryl thioether hydrobromide.

4 Example 5.-p-4-morpholinylethyl benzhydryl ether 40 g. of sodium hydroxide in '10 cc. of water is added to a solution of 97 g. of S-benzhydrylisothiourea hydrobromide in 250 cc. of ethanol. A yellow color develops and the odor of benzhydryl mercaptan is immediately apparent. The mixture is heated for forty-five minutes and then 55.8 g. of ,B-morpholinoethyl chloride hydrochloride added over a period of twenty minutes. Considerable heat is generated during the addition and the solution becomes cloudy. After the addition is complete, 10 g. of sodium hydroxide in 15 cc. of water is added, the mixture stirred for two hours and allowed to stand overnight. Most of the alcohol is removed under reduced pressure, the residue diluted with water and extracted with ether. The ether extract is extracted with two portions of dilute hydrochloric acid. 0n standing, the hydrochloride salt of fi-4-morpholinylethyl benzhydryl ether separates from the acidic extracts. The product is collected and purified by recrystallization from isopropanolligroin mixture; M. P. 179-80 C.

Example 6.fl-Di-n-propylaminoethyl 4,4'-dimethyl benzhydryl thioether GHQ 28.9 g. of B-di-n-propylaminoethyl bromide hydrobromide is added to a solution of 22.8 g. of 4, 1 dimethyl benzhydryl mercaptan in cc. of isopropanol containing 11.3 g. of potassium hydroxide and the resulting mixture warmed on a steam bath for two hours. Most of the solvent is distilled off under reduced pressure, the residue diluted with water and the mixture extracted with ether. The ether extracts are washed with water, dried and the ethef distilled to obtain the crude free base of B-di-n-propylaminoethyl 4,4-dimethyl benzhydryl thioether.

The free base may be converted to its acid oxalate addition salt by adding it to a warm solution of isopropanol containing an equivalent amount of oxalic acid dihydrate. The salt which separates from the solution is collected by filtration and purified by recrystallization from iso propanol.

The citrate salt may be prepared by dissolving the crude free base in ether and adding a saturated ether solution of citric acid. The citrate which separates as a fine powder is collected and purified by repeated washing with dry ether.

Example 7.,8-Methylethylaminoethyl 2- methory benzhydryl thioether 46 g. of Z-methoxy benzhydryl mercaptan is dissolved in 250 cc. of 50% methanol containing 16.5 g. of sodium hydroxide. 31.6 g. of fi-methylethylaminoethyl chloride hydrochloride is added base-and its acid addition in small portions and the mixture warmed on a steam bath for two hours. Most of the methanol is removed by distillation in vacuo, the residue diluted with water and extracted with ether. The ether extracts are washed with water, dried and treated with an excess of dry gaseous hydrogen chloride to convert the free base to the hydrochloride salt. The salt is collected and purified by recrystallization from isopropanol-ligroin mixture.

The mercaptans used as starting materials may be obtained in a number of difierent ways. Perhaps the most convenient method of preparation consists in generating the mercaptan salt in the reaction mixture solution by treatment of the corresponding S-substituted isothiourea hydrohalide with alkali. The S-benzhydryl isothiourea hydrohalides may be obtained by heating a benzhydryl halide with thiourea in alcohol. The S- (9- aminoalkyl) isothiourea hydrohalides may be prepared in a similar manner by reacting a fi-aminoalkyl halide or a hydrohalide salt thereof with thiourea in alcohol. The use of these S-substituted isothiourea hydrohalides as intermediates in the preparation of the mercaptan salts is illustrated more fully in Examples 1, 3 and 5.

Attention is called to the following copending applications which are somewhat related: Serial No. 640,685, filed January 11, 1946; Serial No. 640,686, filed January 11, 1946; Serial No. 640,687, filed January 11, 1946; Serial No. 660,406, filed April 8, 1946; Serial No. 688,420, filed August 5, 1946; Serial No. 688,421, filed August 5, 1946; Serial No. 688,422, filed August 5, 1946; Serial No.

' 688,423, filed August 5, 1946; Serial No. 688,424,

filed August 5, 1946, now Patent No. 2,453,729; Serial No. 688,425, filed August 5, 1946; Serial No. 688,426, filed August 5, 1946, now Patent No. 2,437,711; Serial No. 739,985, filed April 8, 1947, now Patent No. 2,427,878; Serial No. 751,983, filed June 2, 1947, now Patent No. 2,454,092; Serial No. 751,984, filed June 2, 1947; Serial No. 751,985, filed June 2, 1947, now Patent No. 2,455,949; Serial No. 780,099, filed October 15, 1947; Serial No. 15,257, filed March 16, 1948; and Serial No. 33,432, filed June 16, 1948.

What I claim as my invention is:

1. A compound of the class consisting of a free base and its acid addition salts, said free base having the formula where R3 and R4 are members of the class consisting of alkyl radicals containing 1 to 3 carbon atoms inclusive and further members wherein R3 and R4 taken together with N form a saturated six-membered heterocyclic ring.

2. A compound of the class consisting of a free salts, said free base having the formula cmcm n -s-cmc omen. I

aeeaeee 4. A compound of the class consisting of a free base and its acid addition salts, said free base having the formula 5. A compound of the formula CH CHg 6. A compound of the class consisting of a free base and its acid addition salts, said free base having the formula 7. A compound of the formula /CE: CH--B-CH:CH:N

- BIC] 8. Process for obtaining a compound of the formula which comprises reacting a compound of the formula CH- S-M with an w-aminoalkyl halide of the formula where R: and R4 are members of theclass consisting of alkyl radicals containing 1 to 3 carbon atoms inclusive and further members wherein R:

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date OTHER REFERENCES Schonberg et al.,-Ber. deut. chem." vol. 618, pp. 2175-2177 (1928). (Copy in Pet. Ofl. Library.)

Halli et a1. Aug. '6, 1929 

